Striking and boring mechanism



March 6, 1928.

'G. MAEHREN SYTRIKING AND BORING MECHANISM Filed July 1l, 1927 1 Il .Il

NVENTOR ATTORNEY Patented Mar. 6, 1928.

UNITED STATES PATENT OFFICE. l

GEORGE MAEHREN, or NEW tronrnnnr, oALrronNiA, AssreNoR oF erm-HALF To Rocco ELIO, or MONTEREY, CALIFORNIA.

STRIKING AND BORING MECHANISM. i

My invention relates to the class of mechanism that is embodied in tools for carving, boring and other purposes wherein either a percussive bit or a rotary `boring bit may be used. i

A prime object of my invention is to provide a portable tool that may be used to apply a rapid succession of blows to a percussive bit or continuous rotary movement to a boring bit or the like. w

A further object is to provide self-'contained means for disengaging the said percussive element and engaging the rotary element and vice versa.

Another object is to provide a novel facemember for the hammer element of vsaid tool and a complemental element provided on the tang ends of the percussive bits.

A still further object is to provide a socket within said hammer to accommodate said boring-bits.

A further object is to provide external means for changing from either of said movements to 'the other, so as to effect the change without having to interchange any parts of the tool proper;

Another object is to provide anti-friction elements at both sides of the cam elements of the said tool.

Another object is to provide a longitudinally-shifting change-motion member and actuating means therefor.

Other objects are Vto simplify the construction, provide a dual-purposey toolvhaving no interior interchangeable parts to become lost or mislaid, together with other objects and advantages, that will hereinafter appear and be particularly pointed out in the annexed claim.

Referring to the accompanying drawings Figure 1 is an elevation of a tool embodying my invention.

Fig, 2 is a central longitudinal sectional view.

Fig. 3 is a detached elevational view of the change-motion member.

Fig. et is an end view of nal. y

Fig. 5 is an end view of the'driven cam.

Fig. 6 is ya top View of the tang end of a percussive bit. v

Fig 7 ShOWS ,the face of my hammer.

the clutch-jour- Similar reference figures refer to similar parts thruout the different views.

Referring in detail to the drawings; the numeral l denotes the cylindricalv casing of the tool which also forms the take-hold for the operator. .Screwthreaded tothe said casing at the upper end is `thebearing 2, said bearing journaling the `shaft 3 at the `points .4lii and being pro ided with the ample Voil-retaining element 5, and having the inwardly-pro]ecting annular portion o' upon which is pressed the inner member 7 .of an anti-friction element, the outer mem-v ber 8 thereofbeing free for rotation against" the abutting surface of the driving cam 9.

Suitably conformed to co-operate as a supi plemental member to the cam 9 is the driven cam 10, both of which are ground so as to be a nicek lit within the upper endof said casing l. f y The cam l() isfrigidly securedto the shaft 117 the cam 9 being secured to the shaft 3. The shaft l1 is preferably vof round section on the body thereof but itis of square section .from 4the lower'lpart 112L thereof, which entends through the rotary clutchniember l5 and on down to the hammer `member l2 which is secured thereto7 preferably lby screwthreading; the said member lbeing adapted to function as a hammer when reciprocate-d and as a bit-stock when rotated.

Surrounding the saidhammer and with i internal room for either the revolution or -reciprocation thereof is the extension 13' which is adapted to hold bits in alinement -when in operation, the lower portion of said extension being provided with the slot 21 which .is crimped together at the points 22-22 so as to hold the bits against falling out, said points being suitably counterbored at 23 to facilitate the insertion of the bits.

rlhe inner end of the extension 13 being provided with the internally-threaded coupling portion 2a which `screws `on tight against the lower end of the casing l, thereby forming-the seat 25 for the lowerI face of the clutch-member 15 (well shown in Fig. 4) to work against when rotating in the re- 1 cess 14 that is count-erbored in the lower end of the casing l. i Nicely fitted within the body of the casing l is the change-motion member 1G which is provided with the clutch members 17-17 l that are adapted to c11-o11crate with 111e 1'11111- 1111'1111'111111 111111111111115A .1S-,111 1111 the rotary clutchaneuihers 15,-we11 shown 111 Figs. 3 and A'1 respectively. 1511111 inelnber 1G being adapted Vtor longitudinal nloveinent for a certain predetermined length ot stroke, (for a 1'11111111se to be explained) and furnished on the 111111111' c1111 with anti-'Friction 111eans as 1f) for 111e purpose of reducing friction bctween said 1n11n11er 115 111111 the contacting surface 2t) of the driven earn l() when said 1111111111111' is traversed to the right 1111' the '11u11 distance by reversing' 111e cranks tHQtS 11y nun-111s' 111 1h1- thu1111111111s t-BT.

Disposed around the shaft 11H11, .111'- tween the, cluteh 11111111111'1' 11'1 and the. side 21) 111l the 1,':1111 111, and 111 111e annular space hctween said s111111: and the inner wall of the inelnber 111 is 111e 1'1111 spring i215 which is inserted under considerable coinprer'ssion. r1`he Said casing is provided with the oiling 1111111111; 2f) and the bearing with oiling means 30.

The inclnher 16 is not'l turnable within the casing l, being locked against; rotation by the presence ol the cranks Q11 in the slots 2133, as is well shown in Figs. 2 and The square slnrft-portion l1n is adapted for free endwise inovelnentin the clutch ineinber 15, as shown 111 Fig. 4f.

An important feature o1 111e persent invention isthc novel construction o1 n1y 1111111- 111er 'tace tzilien 111 conjunction with its counterpart on the upper ends of my percussive hitze,y as :1'11l1ov111s:-

A11 Shown in Fig. G a halt-round head '11 is raised 1111 the outer 1,'i1'1f1u11terence o1 the said hit, having ay coniplemental groove 3:2 5111111111 the Ytace ot the 1111111111111', Fig. 7. Sai/,1 hannncr 1S further provided with the central hole 3l havingtherein one flat Side Preparatory to the 11511 of the 111111 ity is aS- sunled that the re11uiS11e :1111011111` ot SuitableJ lubricant has been inserted into the 111111 hy the removal and return oit the respective screws 29 and 31), thus providing` for the continuous lubrication ot' all the working parts of Said tool so as to reduce the eo-e11icient ot friction which would otherwise 11e high 111 a tool ot this character, particularly .Q11 with relation to thel working:T 1111181111110 1'11111s 9 and 111 which in 111e present instance run in oil.

s111nin}`r now that a pereus'eivc bit as Si has been Yforced into the extension 13 through the eounter111o1'ed opening 22 which yields Sutiiciently to 111111111. 1111111 bitl and yet: gripe it, with sntiicient tightness to hold 1'1'11111 falling out; and assuming that suitable rotative power is preeentF to revolve the shaft 3 by attachment thereto at the eye 3 and in a clockwise direction; then, with the parts arranged as shown in Fig. 2 the rapid rotation of the Shaft 3 will drive the cani 9 against the cani 10 in such a manner as to apply a. gliding forward movement; to the shaft 11-11' alternated with .sudden 1111111111111' when thc steeper cain-inclines` as EJ" and 111 come in contact during 111e course 111' 1'111'11- lution.

ln this position with the ineinher 11j e11- gaping the rotary elutc11-111e11111er 151 the 1:11- ter held against rotation v.'11i1:-1 the springnr 2S exerts; a atronp1 extensive 11resf1111'1`l hetween the 111111111' Surface ot 111e 1111'111111'1' 1:1 and the lower surface it) o1I the Cain 111. 1111111111: 111 rotateI` the 5111111111-M reciprot'ates rapidly. heine driven in one direction 11 v the 1'11111 111 :11111 111 the other 1111'1111111111111114 2H. I'or. inas- 111111'11 as the .said square portion 1l" 1'111111111 turn in its4 1'11111111'1'11111'1 .square 1111111 in the 1111111111111' 1:1 said shaft is 111111111111111 111 more in the inanner described which cause# the 1111111111111'121111111111 with great rapidity on 1h1- hcad 111l the drill hit. Fig. (1. (h'dinarily, drill-heads to be hannnered on have convex surfaces, but in the present case, havingy 111e hole 3.1. 111 the center of my hannner 'face which has 1.11 11e protected troin being marred or distorted troni its true shape I have provided the aforesaid head 31 on the said drillhead and the groove 3Q on said 1111111111111' .face which now tnnction so that the wear comes on these parts alone as the central portion of the drill-head 81 does not con1c in Contact with the hannner, a construction which pre- Ferves the heads of the 1111s and Saves the said hole intact.

Now, with 111e tool in operation :u a 11ereusive instrument I 11nd that it is unnecessrary to have means incorporated therein 'for regulating 111e Strength o1" the hlows delivered as my spring ia adjusted to throw the 1111111111111' l2 1111 instantiy and the 'f'oree with which the drill Strikes is' in 11ro11ortion 1o the distance the 111111 is held away 1'1'0111 the work.

Assuming' now that; it desirous 1o exchange the percussive drill for a. rota ry hor- 111.11 hit. al1 that it requires is to 11u11 the 111'11:-;- ent; drill out of 111e tool and insert: 11 boring hit having' a 11:11y 1111 the 11111;*r thereof' corres spending to 111e 11111; $15 111 111e 1111111111111' 1Q, and then turn the thinnb-nnts QT through 11 halt eircle. This has the etect 111c throwing)y the 1111111111111' 111 out of engagement' with the 1111x111- her 15 which in now 'tree For revolution, and also throws the anti-friction lneans l.'1i111'on tact with 1111` under surtace 11 of the 1:11111 111 thereby locking 111.11111 1:11111 111e111hers t] 111111 111 together so that they turn as one in 1111191111 with the the 1111111111111' 171` 11'11111 which it 1:1 clear that the change has heen 11111111' 1'1'11111 percuSsive to rotary actuation without any dislncmberlnent ot the tool 11er se o1' 111111' i11- terchang'e of parts thereof.

I do not confine myself to the exact details' of construction of my tool as specitieally 11e- Serihed herein, itbeing hut one embodiment ot the same that my invention may present: in practice, it is to be understood that the yCam at the upper end thereof and a hammer bit-stock at the lower end, means to yieldingly keep the Cams in Contact, a revoluble clutch member journaled in the easing With an axial perforation therethru and 'being adapted to center the lower portion ofsaid shaft, said shaft being unturnable in the perforation, but free for axial displacement, clutch means on said clutch member a nonrevolnble aXially-displaceable change-motion member Within the easingadapted to Contact either with the Complementary cam or the clutch member, oomplemental clutch means oarriedby said Change member and adapted to arrest the revoluble movement otsaid clutch member when engaged therewith, and an antiefrietion means adapted to reduce `the Co-eiioient of friction bet-Ween said change member and the complementary cam aforesaid. f

In testimony whereof I have hereunto set i my hand this 29th day of June, 1927.

GEORGE MAEHREN; 

